The present invention concerns a liquid dispenser for sterile solutions. More particularly, the present invention relates to a multidose dispenser for sterile solutions, particularly in a dropwise form, which keeps the solutions aseptic without the use of preservatives.
A number of solutions which are sold and administered as over-the-counter ("OTC") and/or prescription preparations must be kept sterile to prevent bacterial or other microbial growth. The conventional means of Preventing microbial growth is to add a preservative or other antibacterial agent to the solution during packaging. Although these preservatives keep the enclosed solution sterile, the bottle itself may harbor external bacterial growth which is carried along with the outflow of fluid. In addition, the preservatives themselves are often toxic not just to bacteria but also to the cells which are being treated by the bottled preparation. For example, the preservatives used in most eye drops are toxic to goblet cells and other cells in the eye. Because of this toxicity level, continued use can cause more long term problems then the solutions solve.
Filter bottles have been used to store the solutions in aseptic condition after cold sterilization for many years. Antimicrobial filters, e.g., 0.2 micron filters, are often used for this purpose. However, in many of these previous designs, removal of the fluid required removal of the filter. In other cases, the limitations of flow caused by the small pore size of the microbial filters are not important because the solution is not dispensed through the filters or high pressures are available for dispersing. Because of these and the other problems with filter bottles, the use of preservatives or single dose packaging have been the rule in dispensing OTC and other liquid products such as eye medicants or drops.
Accordingly, an object of the invention is to provide a multidose liquid dispenser which can keep solutions aseptic under prolonged use without the use of an antibacterial or antimicrobial additive.
A further object of the invention is to provide a filter bottle for use in cold sterilization processes which provides good flow properties and protection against bacterial contamination.
Another object of the invention is to provide a bottle which can be used for eye drops and similar solutions which do not contain preservatives.
These and other objects and features of the invention will be apparent from the following description and the drawing.